SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1c4da9cf2e915a93967aacaf613579ab3978bb7dd38dfb4e13e7943b55f408c4' 
  AND token = 'dKaV68qYG+pUxfIRPLbGAE8isn4DvpwpAAPVPIDzhI4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}